Well pipe supporting unit

ABSTRACT

A unit for supporting a well pipe and including a body structure carrying a plurality of pipe gripping slips which are supported by individual vertically movable carriers preferably taking the form of upwardly projecting and vertically moveable posts. These carriers are actuable by an essentially annular cam which is shiftable arcuately about the axis of the gripped pipe by power actuated means. The slips are suspended from the carriers in a manner enabling the slips to move radially outwardly to laterally retracted positions as they are shifted upwardly.

United States Patent 1191 Haby [4 1 Jul 3, 1973 I 1 WELL PIPE SUPPORTING UNIT I751 Inventor: George H. Haby, Altadena, (211111 {73 Assignee: Abegg and Reinhold C0.,Los

Angeles, Calif.

221 Filed: -0664,1971

, 211 Appl. NO.Z 186,096

521 US. c1 24/263 DK 511 Int. Cl A44b 21/00 [58] Field of Search 24/263 DK, 263 DG, 24/263 DA [56] References Cited UNITED STATES PATENTS 1,909,601 '5/1933 Young et 61;; 24/263 DK 2,126,933 8/1938 Stone et a1. 24/263 DG 2,641,816 6/1953 Liljestrand .2 24/263 DG Martin 24/263 DG 3,029,488 4/1962 Knights 24/263 DK 3,230,389 9/1966 Kingsbury 24/263 DG Primary Examiner Paul R. Gilliam Attorney-William P. Green ABSTRACT A unit for supporting a well pipe and including a body structure carrying a plurality of pipe gripping slips which are supported by individual vertically movable r carriers preferably taking the form of upwardly projecting and vertically moveable posts. These carriers are actuable by an essentially annular cam which is shiftable arcuately about the axis of the gripped pipe by power actuated means. The slips are suspended from the carriers in a manner enabling the slips to move radially outwardly to laterally retracted positions as they are shifted upwardly. 7

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INVENTOR. (150265 .71. Haev WELL PIPE SUPPORTING UNIT BACKGROUND OF THE INVENTION circumstances be supported stationarily by a spider, which also normally includes a number of slips.

As deeper and deeper wells have been drilled in recent years, the weight of the casing strings required in these wells has increased so much that conventional elevators and spiders have had great difficulty in supporting this increased weight, and in avoiding damage to the supported heavy strings of pipe. In addition, many of these conventional elevators and spiders are relatively difficult to actuate between gripping and released conditions, with resultant expenditure of excessive time and effort in actuating and releasing them during the lowering or withdrawal of an extended length of easing.

SUMMARY OF THE INVENTION The present invention provides an improved well pipe supporting unit which is especially well adapted for supporting these extremely long strings of casing or .the suspended pipe. Similarly, the casing may in some other well pipe. As will appear, the mechanical construction and method of operation of these supporting units are such as to maximize the load supporting capacity of the units while avoiding an excessive increase in their size or weight. Further, the devices are very positively and quickly actuable by built-in powered means between gripping and released conditions. Certain particular features of the invention relate to a preferred manner in which the slips may be cammed inwardly toward a pipe first at a relatively rapid rate to effectively center the pipe in the device, and then at a reduced rate to set the slips in final gripping condition.

With regard to structure, a unit embodying the inven-' tion includes a slip actuating cam structure which extends and moves arcuately about the'axis of the gripped pipe. A plurality of slips are mounted movably to the body of the device by individual carrier parts, preferably taking the form of vertically moveable posts slidably received within and projecting upwardly from mounting sockets or guideways in the body structure.

The slips are mounted to these carriers by connections which allow radially outward retracting movement of the slips upon upward movement thereof by the cam mechanism. Desirably,,the body structure is formed as a plurality of body sections which are openable to a condition allowing removal of the unit laterally from about a pipe, and the cam structure may be formed similarly as a plurality of sections mounted to the various body sections respectively. Piston and cylinder mechanisms or other power units are mounted on the different body sections for actuating the corresponding cam sections relative thereto.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawings in which:

FIG. 1 is a somewhat diagrammatic representation of a portion of a well drilling rig having an elevator constructed in accordance with the invention;

FIG. 2 is a fragmentary perspective view of the elevator of FIG. 1, with one-half of the upper cover removed to reveal the inner mechanism of the apparatus;

FIG. 3 is a plan view of the elevator taken on line 33 of FIG. 1;

FIG. 4 is an enlarged horizontal section taken on line 4-4 of FIG. 2 just beneath the top wall of the cover part;

FIG. 5 is an enlarged fragmentary vertical section taken on line 5-5 of FIG. 4;

FIG. 5a is a horizontal section taken on line 5a'-5a of FIG. 5;

FIG. 6 is a fragmentary view similar to a portion of FIG. 4, but showing the slips in their retracted positions;

FIG. 7 is a fragmentary vertical section taken on line 77 of FIG. 6;

FIG. 8 is a fragmentary vertical section taken on line 8-8 of FIG. 7;

FIG. 9 is a fragmentary view of the cam taken essentially on line 9-9 of FIG. 5;

FIG. 10 is a view similar to FIG 9 but taken on line 10-10 of FIG. 7;

FIG. 11 is an enlarged fragmentary vertical section taken on line 1111 of FIG. 4;

FIG. 12 is a view taken on line 1212 of FIG. 4; and

FIG. 13 is a fragmentaryvertical section taken on line 1313 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, I have shown at 10 a well pipe supporting unit constructed in accordance with the invention and illustrated as it appears when in use as an elevator, for suspending and moving vertically a string of easing or other well pipe, .the upper stand of which is represented at 11. The casing extends downwardly along a vertical axis 12 through the usual rotary table represented diagrammatically at 13, and into the well. Elevator 10 is itselfsuspended and actuated upwardly and downwardly by the conventional hoisting mechanism of the rig, including a power actuated block and tackle 14 whose traveling block 15 carries a main hook 16 having two smaller side hooks 16a supporting the elevator through a pair of vertical support rods 18.

When it is desired to utilize the well pipe supporting unit 10 as a spider rather than an elevator, support rods 18 may be detached from the remainder of the unit, and the unit may then be supported on the rotary table in appropriate manner to suspend the pipe 11 in stationary position.

Unit 10 includes a generally annular rigid and very strong body 19 extending about the suspended casing 11 and its axis 12, and preferably consisting of two identical complementary essentially semicircular halves or sections 20 and 21 meeting'in the vertical diametrical plane represented at 22 in FIG. 4. At the two diametrically opposite locations at which the opposite ends of the two body sections 20 and 21 meet, these body sections have interfitting connector or hinge lugs 23 (see FIG. 12), containing vertically aligned registering cylindrical apertures or passages 24 within which two vertical externally cylindrical hinge or connector pins 25 are removably received to releasably secure the two body sections together in their FIG. 4 assembled relation. These pins 25 are centered about and extend vertically along two parallel vertical axes 26 and 27 (FIG. 4) which are positioned symmetrically and at diametrically opposite sides with respect to the main axis 12 of the tool and casing. Pins 25 are of course close fits within the apertures 24, and may have slightly enlarged upper heads 28 limiting downward movement of the pins relative to the body sections in the FIG. 12 assembled condition of the parts, with one or both of the pins desirably having a loop or bail 29 at its upper end by which the pin may be grasped to pull it upwardly from the body sections and thus detach the body sections for removal laterally from about the casing.

At opposite sides of each of the two pins 25, body sections 20 and 21 carry two identical upstanding suspension lugs 30 and 31, having aligned openings 32 receiving a horizontal pin 33 about which a lower eye portion 34 of one of the rods 18 is received in suspending relation. A spacer bushing 35 may be received about each of the pins 33 and between lugs 30 and 31, with pin 33 desirably having an enlarged head 36 at one of its ends adapted to be detachably connected to the associated lug 31 by a screw or other fastener 37.

In normal use, the two body sections will ordinarily be left in their connected assembled condition, with the body and carried parts being removed from about the casing by withdrawing unit upwardly past the upper end of the casing. If circumstances arise in which it becomes necessary to remove the unit 10 from about the casing by movement in a lateral direction, the two'pins 33 maybe detached from the body sections, and one of the vertical pins 25 may then be withdrawn upwardly out of its position of connection to the hinge or connector lugs 23, to thus release the two body sections and 21 for relative opening or swinging movement about the second of the two vertical pins as a hinge, and to an open position such as that represented in broken lines in FIG. 3, in which the entire unit may be easily moved laterally from about the casing.

At their lower ends, the two body sections 20 and 21 carry two complementary semicircular downwardly projecting centering or locating elements 38, suitably secured to the body sections as by bolts 39, and having downwardly flaring frustoconical portions 40 which are engageable with the upper end of the casing as the unit 10 is moved downwardly about the casing, to automatically deflect the unit 10 laterally to a properly centered relation with respect to the pipe. The two semicircular elements of course meet or substantially meet in the same plane 22 of FIG. 4 in which the body sections 20 and 21 meet.

Within the body structure 19 formed by sections 20 and 21, there arecarried several (preferably 4) identical pipe gripping slips 41, whose inner faces carry gripping dies 42 engageable with the pipe to suspend it and hold it in fixed position when the slips are in their set or active conditions. Each of the slips extends arcuately through approximately 90 degrees about vertical axis 12, with two of the slips being contained within body section 20 and the other two being contained. within body section 21, and with the slips carried by each body section having vertical end faces 42 which lie approximately in the vertical plane of separation 22 of the two halves of the unit. The vertical surfaces of the two body sections which meet in this plane are represented at 43' in FIG. 4. At their radially outer sides, slips 41 have downwardly tapering frustoconical wedge surfaces 43, 44, and 45 which engage correspondingly shaped wedge surfaces 46, 47, and 48 (FIG. 5) on the body sections 20 and 21, to cam or wedge the slips radially inwardly relative to the body section upon'downward movement of the slips, and thus support the casing. Preferably, the camming surfaces on the slips and body sections are formed in stepped fashion, as seen in FIG. 5, so that when the slips are moved upwardly a relatively short distance to the FIG. 7 inactive position, the stepped interfitting relationship between the slips and body sections enables the slips to move radially outwardly far enough to allow movement of the entire assembly upwardly past the upper end of the casing.

Each of the slips 41 is suspended by an individual hanger 49 (FIGS. 5, 7, 8, and 13), which as seen best in FIG. 13 has a horizontal base portion 50 secured by screws 51 to the upper surface 42 of the slip. Two parallel vertical portions 52 of the bracket project upwardly in spaced relation, and may be interconnected by a cross web 53. Above web 53, the upstanding portions 52 of bracket 49 form a recess or guideway 54 de-- fined by two parallel planar inner surfaces 55 lying in planes which are parallel to and spaced equally in opposite directions from a vertical diametrical plane 56 containing the main vertical axis 12 of the tool. Also, as seen best in FIGS. 5 and 7, the two upstanding portions 52 preferably extend angularly radially outwardly as they advance upwardly above a location 57' near the level of cross web 53.

For slip supporting coaction with the brackets 49 of the various slips 41, there are provided a number of support posts or columns 57 mounted by the body sections 20 and 21 for upward and downward movement relative thereto. Each of these-posts57 is externally cylindrical and centered about a vertical axis 58 extending parallel to main vertical axis 12. The four axes 58 of the four posts 57 are equally spaced circularly about axis 12, with two of the posts being carried by body sec tion 20, and the other two posts being carried by body section 21, as seen best in FIG. 4. Each of the posts 57 is received telescopically within a coacting vertical cylindrical passage or guideway 59 in the corresponding body section, and is a sufficiently close fit in that passage to effectively guide the post for only vertical movement. If desired, a portion or all of the passage 59 may be lined by an appropriate bushing 60 to enhance the'effectiveness of the mounting of the post. A coil spring 61 is contained within the lower portion of each of the passages 59, and is seated at its lower end-on a reduced diameter shoulder portion 62 of passage 59, so that the spring yieldingly urges the associated post 57 upwardly from the FIG. 5 position toward a position just short of or under the FIG. 7 setting of the post. The force ofeach spring 60 is just sufficient to overcome the weight of the associated slip 41, bracket 59, and the bracket engaging structure carried at the upper end of the post.

That bracket engaging structure at the upper end of each post includes a head element 63, which is' appropriately rigidly connected to the upper end of the associated post 57, as by providing head 63 with a vertical cylindrical passage 64 in which the upper end of the post is a tight forced or friction fit holding the parts in the illustrated assembled relation. In extending upwardly from the lower horizontal undersurface 65 of head 63, this part may be of square cross section, up to the level 66 of FIG. 5, to have a planar vertical radially inner surface 67 and a parallel planar vertical radially outer surface 68, both of which are perpendicular to the previously mentioned radially extending'vertical plane 56. Projecting radially outwardly from surface 68, each of the heads 63 has a roller 70 mounted to turn relative to head 63 about a horizontal axis 71 (FIG. 5) which lies in the plane 56 of FIG. 5a. This A. roller 70 is received and closely confined within a vertical guideway 72 in an upstanding bifurcated guide element 73 projecting upwardly from a horizontal plate 74 secured rigidly to the upper surface 75 of the corresponding one of the two body sections m 21. The vertical guideway 72 thus guides roller 70 for only vertical movement, and thereby prevents post 57 from turning about its axis 58 upon upward movement of the post and carried structure.

At its upper end, each of the post carried head elements 63 has a generally radially inwardly projecting arm 76, having parallel planar opposite side faces 77 which lie in two vertical planes parallel to the plane 56 of FIG. 13 and spaced very slightly from surfaces 55 of bracket 49, to allow movement of bracket 49 radially inwardly and outwardly relative to main axis 12 and relative to the post carried head element 63. To further guide each of the slip mounting brackets 49 and the associated slip for such essentially radial movement relative to axis 12, the spaced upperportions 52' of the bracket 49 carry at their inner sides two pairs of guide rollers 78, with one of the pairs being carried by each of the projections 52 and with these rollers turning about two axes 79 and 80 as seen in FIGS. 5 and 13. These rollers are received and confined within two parallel coacting track guideways 81 formed in the opposite sides of arm 76 of head element 63, to hold each bracket 49 and carried slip 41 in a fixed orientation with respect to the corresponding post 57 while guiding the bracket and slip for its generally radial movement.

1 As seen clearly in FIGS. 5 and 7, the tracks 81 are inclined slightly, and the axes 79 and of the rollers 78 are correspondingly offset vertically as well as horizontally, to guide the brackets and slips for movement along slightly inclined paths which advance downwardly as the slips move radially outwardly. As a result, when the posts 57 and carried parts are elevated upwardly above the FIG. 5 position and toward the FIG. 7 position, the weight of the slips will by gravity cause the slips and their brackets 49 to move radially outwardly to their laterally retracted positions of FIG.' 7. Conversely, when the slips are supported by the body sections 20 and 21 upon downward movement of posts metrically opposite end face 86, while section 84 has two similar and closely adjacent end faces 87 and 88. In the FIG. 4 active setting of the slips, these end faces 85, 86, 87, and 88 of the two cam sections lie in an axial plane 89 which is offset circularly from the previously discussed plane of separation 22 of the two body sections. When, however, the cam structure is turned about axis 12 to the retracted-slip setting of FIGS. 6 and7, the end faces 85, 86, 87, and 88 of the cam sections all lie essentially in the discussed plane of body section separation 22, so that the cam sections as well as the remainder of the apparatus can be swung to the open condition shown in broken lines in FIG. 3.

The'two cam sections 83 and 84 are actuable in unison between their discussed different settings of FIGS. 4 and 6 by means of two power actuated units, preferably taking the form of two piston and cylinder mechanisms 89 carried by the two body sections 20 and 21 respectively. More particularly, the cylinder of each of the mechanisms 89 may be secured pivotally at 90 to a portion of the previously mentioned plate 74 carried by one of the body sections, whilethe piston rod of that mechanism 89 may be secured pivotally at 91 to a portion of the associated cam section 83 or 84. An appropriate control valve diagrammatically represented at 92 in FIG. 4 supplies pressurized fluid to the two piston and cylinder mechanisms 89 simultaneously to actuate them at the same time in either desired direction.

The cam sections 83 and 84 are appropriately guided for only circular movement about axis 12, as by suitable roller type bearings mounted rotatably to the body carried plates 74. More specifically, each of the plates 74 may carry several circularly spaced rollers 93 (FIG. 11) at the underside of the associated cam section 83 or 84, received and confined within an arcuate bottom recess or guideway 94 in that cam section, and may also carry a second group of circularly spaced rollers 95 for engaging an arcuate guide surface 96 formed at the upper side of-a flange 97 on the corresponding cam section 83 or 84. The rollers 93 turn about horizontal axes 98 which extend radially outwardly from the main vertical axis 12 of the, tool, while rollers 95 turn about vertical axes 99, and have inclined annular frustoconical bearing surfaces 100 engaging the correspondingly inclined surfaces 96 on the cam sections.

In order to effect upward and downward movement of posts 57 and the carried slips in response to arcuate movement of the cam sections 83 and 84 about axis 12, the cam sections are provided with four camming slots or guideways 101 (FIGS. 5, 7, 9, and 10), which receive four cam follower rollers 102 mounted rotatably to the four head elements 63 carried by the four posts 57 respectively. Each of these rollers 102 may turn about the corresponding radial axis 56 of FIG. 5a, and project radially inwardly from the inner surface 67 of the corresponding head 63. As seen best in FIGS. 9 and 10, each c'am slot 101 has a camming surface'103 defining the upper side or edge of the slot and which is inclined to advance vertically as it advances arcuately about axis 12, upon arcuate movement of cams 83 and 84 from the FIG. 10 position to the FIG. 9 position, each roller 102 engages the corresponding cam surface 103 and is'deflected downwardly thereby, against the resistance offered by the associated spring 61, to thus cause downward shifting move-ment of the slips in response to predetermined arcuate movement of the cam sections. As seen clearly in FIG. 9, surface 103 has two portions of different inclination, including a first portion of relatively great inclination from point 203 to point 303, and a second and preferably shorter portion of reduced inclination from point 303 to the extremity 403 of the'slot. Thus, the slips are first cammed downwardly at a relatively rapid rate, with resultant rapid radially inward movement of the. slips, and are then cammed very slowly downwardly and inwardly as the follower moves along the reduced inclination surface to the final pipe gripping position of FIG. 9. The initial rapid movement allows for positive forced centering of the pipe by the slips, even though the pipe may initially be offset a substantial distance from a properly centered position of alignment with the well axis, while the final slow movement permits a more gradual but still positive and forced ultimate setting of the slips into gripping contact with the pipe.

In the FIG. retracted setting of the slips, each cam follower 102 is received within a shallow detenting notch 105 formed in an upwardly facing horizontal surface 106 which merges with the inclined bottom edge wall 206 of the corresponding slot 101. As will be apparent, springs 60 urge the slips and cam followers 102 upwardly only to approximately the level of the follower 102 in FIG. 10, so that the weight of the slips and associated parts can maintain the followers 102 in detenting positions within notches 105.

To protect the working parts of the tool, the body sections may carry two complementary essentially semicircular covers 107, secured by bolts 108 to the top of the body sections, and meeting in the previously mentioned plane of separation 22. The inner edges of these covers may carry two semicircular complementary flange elements defining together an opening dimensioned to receive the well casing 11, and to pass its upper enlarged tool joint end.

To now describe a cycle of use of the tool, assume that the apparatus is initially in the completely assembled condition illustrated in the figures, and that the slips and their actuating parts are in the retracted positions of FIGS. 6, 7, and 10. In this condition, the tool can be moved downwardly past the upper end of well pipe 11 and to the FIG. 1 position. When in that position, an operator actuates control valve 92 to cause the piston and cylinder mechanisms to move cam sections 83 and 84 arcuately and at an essentially uniform rate from their FIG. 6 positions to their FIG. 4 positions, to thereby move the cam slots 101 between their FIG. 10 and FIG. 9 settings. This actuation of the cam sections causes the cam follower rollers 102 to move downwardly to their FIG. 9 positions, to this actuate each of the posts 57 downwardly against the tendency of the associated spring 61 and to the FIG. 5 setting, with resultant lowering of the slips and forced inward deflection thereof, first rapidlyfor centering and then more slowly for final setting, to their active positions of gripping engagement with the well pipe. As the posts and slips move downwardly, the inclined surfaces 43, 44, 45, 46, 47,'and 48 on the slips and body sections cam the slips radially inwardly, with rollers 78 of hangers 49 enhancing this effect and moving radially inwardly along guideway tracks 81 ofpost carried head elements 63 from the FIG. 7 position to the FIG. 5 position of the hangers. When the slips have thus been engaged with the-casing 11, the casing can be moved upwardly or downwardly as desired to add or subtract a length of pipe by actuation of the suspending hoist mechanism 14. In the FIG. 9 position of the cam mechanism, in which the slips are set tightly against the casing, the cam follower rollers are not normally at the end of their range of possible movement beyond points 303, but rather have remaining and unused space for overtraveling movement beyond that set position, in order to allow for effective gripping of pipes of different external diameters.

When it is desired to release the casing from the support unit 10, the operator actuates the control valve to move the cam sections arcuately back to the setting of FIGS. 6, 7, and 10, to return the posts and carried parts back upwardly to the FIG. 7 position, with resultant automatic radially outward retraction of the slips by gravity as the hanger-rollers 78 move outwardly along the inclined guideway tracks 81. Engagement of the cam followers 102 with inclined surfaces 206 of the slots cams the followers and slips upwardly in a positive manner during such slipreleasing actuation.

If it becomes necessary at any time to remove the tool laterally from about the pipe, the slips are actuated to their retracted positions, the two pins 33 and one of the pins 25 are removed as previously described, and the entire assembly may then be swung open to the broken line position of FIG. 3.

While a certain specific embodiment of the present invention has been disclosed as typical, the invention is of course not limited to this particular form, but rather is applicable broadly to all such variations as fall within the scope of the appended claims.

I claim:

1. A well pipe supporting unit comprising a body structure to extend about a pipe, a plurality of slips movable upwardly and downwardly relative to said body structure between lower active pipe gripping positions and upper retracted positions, inclined surfaces for deflecting said slips inwardly against a pipe upon downward movement of the slips, an actuating structure extending generally arcuately about the axis of said pipe and' mounted to turn about said axis relative to said body structure and said slips, a plurality of generally vertical slip carrier posts mounted to said body structure at circularly spaced locations for longitudinal upward and downward movement relative to the body structure along individual axes, coacting cam means on said posts and said actuating structure operable to cam the posts upwardly and downwardly in response to turning movement of the actuating structure about said pipe axis, and a plurality of connections suspending upper portions of said slips from said different posts respectively for upward and downward movement therewith and for radially outward and inward movement relative to said-posts upon said upward and downward movements respectively.

2. A well pipe supportingunit as recited in claim 1, including power operated means for moving said actuating structure essentially arcuately about said axis of the pipe.

3. A well pipe supporting unit as recited in claim 1, including means yieldingly urging said slip carrier posts upwardly relative to said body structure.

4. A well pipe supporting unit as recited in claim 1, in which said actuating structure is essentially annular, said cam means including a plurality of inclined cam slots in said actuating structure which advance vertically as they advance circularly about said axis, and a plurality of cam follower rollers mounted rotatably to said posts and received in said slots for actuation upwardly and downwardly upon rotary movement of the actuating structure.

v5. A well pipe supporting unit as recited in claim 1, including projections on said posts extending laterally with respect to said individual axes of the posts, and a plurality of guideways receiving said projections in a relation enabling upward and downward movement of the posts relative to the body structure but restraining the posts against turning movement about said individual axes.

6. A well pipe supporting unit as recited in claim 1, in which said body structure contains a plurality of circularly spaced socket recesses slidably receiving said posts and guiding them for said upward and downward movement along said individual axes, there being a plu rality of rollers mounted rotatably to said posts respectively to turn about generally horizontally axes,and generally vertical guideways carried by the body structure and movably receiving said rollers in a relation allowing upward and downward movement thereof while restraining turning movement of the posts about their individual axes.

7. A well pipe supporting unit as recited in claim 1, in which said connections include inclined track means carried by said posts, and hangers projecting upwardly from and suspending said slips and engaging and suspended by and movable along said track means.

8. A well pipe supporting unit as recited in claim 1, in which said body structure includes a plurality of complementary body sections relatively movable to an open condition enabling movement of the body structure from about the pipe, said actuating structure being essentially annular and including a plurality of complementary essentially arcuate sections carried by said body sections respectively for relative opening movement therewith, there being a plurality of powered mechanisms carried by said body sections respectively for moving said sections of the actuating structure arcuately relative thereto.

9. A well pipe supporting unit as recited in claim 1, in which said posts have lower portions mounted within circularly spaced socket recesses in said bodystructure and guided thereby for said upward and downward movement relative to the body structure, there being springs yieldingly urging said posts upwardly, each of said connections including an arm structure projecting generally radially inwardly from an upper portion of one of said posts and forming track means, and a bracket attached to the associated one of said slips and projecting upwardly therefrom and-having roller means movable generally radially inwardly, and outwardly in said track means, said track means being inclined to urge said roller means and suspended slip radially outwardly along said track means by gravity in response to the downward forces exerted by the weight of said slip 2 when the carriers and slips are raised upwardly;

10. A well pipe supporting unit as recited in claim 9, in which said body structure is formed of two complementary halves interconnected for relative opening movement to enable removal of the well pipe supporting unit from about a well pipe, said actuating structure being essentially annular and formed of two complementary halves movably carried by said two body halves respectively and relatively openable therewith,

- there being two piston and cylinder mechanisms carried by said two body halves respectively for moving said two halves respectively of the actuating structure relative to the-associated body sections.

1 l. A well pipe supporting unit as recited in claim 10, in which said actuating structure is located at a radially inner side of said posts and beneath said inwardly projecting arm structures, said cam means including a cam follower roller carried at a radially inner side of each of said posts and engaging a coacting cam slot formed in said actuating structure, there being a second roller carried at the radially outer side of each of said posts, and guideways carried by the body structure and receiving said last mentioned rollers in a relation permitting upward and downward movement thereof while preventing turning of the posts about their individual axes.

12. A well pipe supporting unit as recited in claim 1, in which said cam means include a plurality of inclined cam surfaces and engaging followers, said cam surfaces having first portions of relatively abrupt inclination acting upon initial arcuate movement said actuating structure to cause movement of the slips downwardly and inwardly at a relatively rapid rate, and said cam surfaces having second portions of less abrupt inclination acting to then automatically convert to a slower rate of downward and inward. movement of the slips upon further downward movement of the actuating structure.

13. A well pipe supporting unit comprising a body structure to extend about a pipe, a plurality of slips movable upwardly and downwardly relative to said body structure between lower active pipe gripping positions and upper retracted positions, inclined surfaces for deflecting said slips inwardly against the pipe upon downward movement of the slips, an actuating structure mounted for movement generally horizontally relative to said body structure, and cam means associated with said actuating structure and at least one of said slips for effecting downward movement of said slip upon said generally horizontal movement of the actuating structure, said c'am means including an inclined cam surface and a cam follower engaging said cam surface, said cam surface having a first portion of relatively abrupt inclination acting upon initial horizontal movement of said actuating structure to cause movement of the slips downwardly and inwardly at a relatively rapid rate, and said cam surface having a second portion of less abrupt inclination acting to then automatically convert to a slower rate of downward and in ward movement of the slips upon further movement of the actuating structure.

14. A well pipe supporting unit as recited in claim 13,

in which said actuating structure extends essentially arcuately about the axis of said pipe and has said camming surface formed thereon, said cam follower being connected to said one of the slips for movement therewith. f

15. A well pipe supporting unit as recited in claim 14, in which said actuating structure has a detent notch engageable by said follower in a relation releasably retaining said follower in an uppermost setting of the associated slip.

16. A well pipe supporting unit as recited in claim 13, in which said actuating structure extends generally annularly about the axis of said pipe and has a plurality of inclined cam slots engaging and actuating a plurality of said cam followers connected to said slips respectively, there being a-plurality of said inclined camming surfaces defining upper edges of said slots respectively and each having a first portion of relatively great inclislots defining upwardly facing detent notches in which nation and a lower end portion of reduced inclination, said followers are releasably retained in upper positions there being surfaces at undersides of the slots having of the slips.

generally horizontal portions at the upper ends of the 

1. A well pipe supporting unit comprising a body structure to extend about a pipe, a plurality of slips movable upwardly and downwardly relative to said body structure between lower active pipe gripping positions and upper retracted positions, inclined surfaces for deflecting said slips inwardly against a pipe upon downward movement of the slips, an actuating structure extending generally arcuately about the axis of said pipe and mounted to turn about said axis relative to said body structure and said slips, a plurality of generally vertical slip carrier posts mounted to said body structure at circularly spaced locations for longitudinal upward and downward movement relative to the body structure along individual axes, coacting cam means on said posts and said actuating structure operable to cam the posts upwardly and downwardly in response to turning movement of the actuating structure about said pipe axis, and a plurality of connections suspending upper portions of said slips from said different posts respectively for upward and downward movement therewith and for radially outward and inward movement relative to said posts upon said upward and downward movements respectively. Pg,17
 2. A well pipe supporting unit as recited in claim 1, including power operated means for moving said actuating structure essentially arcuately about said axis of the pipe.
 3. A well pipe supporting unit as recited in claim 1, including means yieldingly urging said slip carrier posts upwardly relative to said body structure.
 4. A well pipe supporting unit as recited in claim 1, in which said actuating structure is essentially annular, said cam means including a plurality of inclined cam slots in said actuating structure which advance vertically as they advance circularly about said axis, and a plurality of cam follower rollers mounted rotatably to said posts and received in said slots for actuation upwardly and downwardly upon rotary movement of the actuating structure.
 5. A well pipe supporting unit as recited in claim 1, including projections on said posts extending laterally with respect to said individual axes of the posts, and a plurality of guideways receiving said projections in a relation enabling upward and downward movement of the posts relative to the body structure but restraining the posts against turning movement about said individual axes.
 6. A well pipe supporting unit as recited in claim 1, in which said body structure contains a plurality of circularly spaced socket recesses slidably receiving said posts and guiding them for said upward and downward movement along said individual axes, there being a plurality of rollers mounted rotatably to said posts respectively to turn about generally horizontally axes, and generally vertical guideways carried by the body structure and movably receiving said rollers in a relation allowing upward and downward movement thereof while restraining turning movement of the posts about their individual axes.
 7. A well pipe supporting unit as recited in claim 1, in which said connections include inclined track means carried by said posts, and hangers projecting upwardly from and suspending said slips and engaging and suspended by and movable along said track means.
 8. A well pipe supporting unit as recited in claim 1, in which said body structure includes a plurality of complementary body sections relatively movable to an open condition enabling movement of the body structure from about the pipe, said actuating structure being essentially annular and including a plurality of complementary essentially arcuate sections carried by said body sections respectively for relative opening movement therewith, there being a plurality of powered mechanisms carried by said body sections respectively for moving said sections of the actuating structure arcuately relative thereto.
 9. A well pipe supporting unit as recited in claim 1, in which said posts have lower portions mounted within circularly spaced socket recesses in said body structure and guided thereby for said upward and downward movement relative to the body structure, there being springs yieldingly urging said posts upwardly, each of said connections including an arm structure projecting generally radially inwardly from an upper portion of one of said posts and forming track means, and a bracket attached to the associated one of said slips and projecting upwardly therefrom and having roller means movable generally radially inwardly and outwardly in said track means, said track means being inclined to urge said roller means and suspended slip radially outwardly along said track means by gravity in response to the downward forces exerted by the weight of said slip when the posts and slips are raised upwardly.
 10. A well pipe supporting unit as recited in claim 9, in which said body structure is formed of two complementary halves interconnected for relative opening movement to enable removal of the well pipe supporting unit from about a well pipe, said actuating structure being essentially annular and formed of two complementary halves movably carried by said two body halves respectively and relatively openable therewith, there being two piston and cylinder mecHanisms carried by said two body halves respectively for moving said two halves respectively of the actuating structure relative to the associated body halves.
 11. A well pipe supporting unit as recited in claim 10, in which said actuating structure is located at a radially inner side of said posts and beneath said inwardly projecting arm structures, said cam means including a cam follower roller carried at a radially inner side of each of said posts and engaging a coacting cam slot formed in said actuating structure, there being a second roller carried at the radially outer side of each of said posts, and guideways carried by the body structure and receiving said last mentioned rollers in a relation permitting upward and downward movement thereof while preventing turning of the posts about their individual axes.
 12. A well pipe supporting unit as recited in claim 1, in which said cam means include a plurality of inclined cam surfaces and engaging followers, said cam surfaces having first portions of relatively abrupt inclination acting upon initial arcuate movement said actuating structure to cause movement of the slips downwardly and inwardly at a relatively rapid rate, and said cam surfaces having second portions of less abrupt inclination acting to then automatically convert to a slower rate of downward and inward movement of the slips upon further downward movement of the actuating structure.
 13. A well pipe supporting unit comprising a body structure to extend about a pipe, a plurality of slips movable upwardly and downwardly relative to said body structure between lower active pipe gripping positions and upper retracted positions, inclined surfaces for deflecting said slips inwardly against the pipe upon downward movement of the slips, an actuating structure mounted for movement generally horizontally relative to said body structure, and cam means associated with said actuating structure and at least one of said slips for effecting downward movement of said slip upon said generally horizontal movement of the actuating structure, said cam means including an inclined cam surface and a cam follower engaging said cam surface, said cam surface having a first portion of relatively abrupt inclination acting upon initial horizontal movement of said actuating structure to cause movement of said one slip downwardly and inwardly at a relatively rapid rate, and said cam surface having a second portion of less abrupt inclination acting to then automatically convert to a slower rate of downward and inward movement of said one slip upon further movement of the actuating structure.
 14. A well pipe supporting unit as recited in claim 13, in which said actuating structure extends essentially arcuately about the axis of said pipe and has said camming surface formed thereon, said cam follower being connected to said one of the slips for movement therewith.
 15. A well pipe supporting unit as recited in claim 14, in which said actuating structure has a detent notch engageable by said follower in a relation releasably retaining said follower in an uppermost setting of the associated slip.
 16. A well pipe supporting unit as recited in claim 13, in which said actuating structure extends generally annularly about the axis of said pipe and has a plurality of inclined cam slots engaging and actuating a plurality of said cam followers connected to said slips respectively, there being a plurality of said inclined camming surfaces defining upper edges of said slots respectively and each having a first portion of relatively great inclination and a lower end portion of reduced inclination, there being surfaces at undersides of the slots having generally horizontal portions at the upper ends of the slots defining upwardly facing detent notches in which said followers are releasably retained in upper positions of the slips. 